Good morning
I am an old (63YO) audio enthusiast with very little soldering skills (acquiring some).
My sound system consists of Class D amps (Samwu TPA3118, Weiner, and lately a 3255EVM which I swap on whim outputing to a pair of Tannoy bookshelves.
My sources are a TV, DVD player and a Digital Box which plays FLAC, WAV and MP3s
For volume control, I route the input signal to a cheap 2-tube buffer. I was able to buy an external switch to select sources but it is flakey.

I would like to assemble a pre-amp with minimum work, hopefully forgiving in the soldering area. And if possible the minimum number of components and cost.
Would anyone please advise me whether the Bi or the Mesmerize (or other circuti) would fit my requirements.
I have very little info about these circuits except that they have a selectable input and very good reputation for sound output.
Thank you.

The B1 feeds the power amplifier.
For phono you use:
phono > RIAA pre-amp > B1 > power amp
or
phono > RIAA pre-amp > tube buffer > B1 > power amp
You would need the tube buffer only if your RIAA pre-amp cannot adequately drive the cables to the next stage.

The B1 accepts two inputs, whereas the DCB1 based Mezmerise has upto six inputs.